A group of 38 British people who developed narcolepsy after receiving the “Pandemrix” swine flu vaccine have launched a legal claim against its manufacturer.

The Government admitted in September that evidence suggests the jab can cause the neurological disorder, which results in excessive drowsiness and severely disrupted sleeping patterns.

Lawyers representing the group, most of whom are children, claim each could be due to £1 million in compensation after launching a class action against its manufacturer, GlaxoSmithKline (GSK).

But any award is likely to be paid for by the taxpayer because an indemnity agreed between GSK and the Department of Health states that any compensation claims and costs must be paid by the government.

The vaccine was administered to high-risk groups including children and adults with asthma, diabetes and heart disease at the height of the swine flu pandemic in 2009-10.

Evidence compiled by the Health Protection Agency earlier this year suggests that about one in 55,000 vaccinated children – or about 20 in total in the UK – may have gone on to develop narcolepsy.

The condition causes serious disruption to patients’ sleep and everyday life, and in some cases sufferers develop a related condition called cataplexy which results in total loss of muscle control.

Peter Todd, a solicitor at Hodge Jones & Allen, who is representing the 38 families, described the indemnity agreed between GSK and the government as “almost unprecedented”.

He added: “I did not expect GSK to invoke their entitlement to be indemnified by the UK Government – however they have done so immediately after the UK Government itself admitted a link between the vaccine and narcolepsy.

“Narcolepsy is a serious, incurable condition requiring a lifetime of medication and management. Many of the activities that most people take for granted can be totally compromised, such as study, work and the ability to have sole care of young children. The innocent victims of this deserve support and provision for their futures.”

A GSK spokesman said the government had agreed to “manage and share the responsibility of any legal claims” because of the “unprecedented” scale and speed of vaccination programmes against H1N1 pandemic flu.

“Patient safety is our number one priority and we are actively researching how narcolepsy is triggered and how this vaccine might have interacted with other risk factors in affected individuals,” they added.

A Department of Health spokesperson said: “We are aware of this claim and are working with GlaxoSmithKline to consider it as quickly as practicable.”